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Li-Po batteries can be highly dangerous, and many people have no idea!
For years, lithium polymer batteries (Li-Pos) have been known to be dangerous and unpredictable. Dropping, denting or crushing can shorten the life of the battery and even cause an internal short — a recipe for fire. There are a myriad of guidelines for storing, charging and transporting them. Even among experienced RC users, they have led to fires.
The #1 tip is to never leave a Li-Po battery unattended during the charging or discharging process.
Before Charging Li-Po Batteries
- The #1 tip here is: RTFM (Read the F~*#ing Manual!)
- Always check the voltage of batteries before each charge session in order to ensure they are at or above the minimum safe starting voltage. If their starting voltage is below recommended levels then your batteries have been over-discharged or have experienced a failure and should NOT be charged.
- Always check the battery before charging for any type of damage. Check the battery packaging, wires and connectors for defects, which may cause a short circuit and eventual battery failure.
Charging Li-Po Batteries
- Only use a charger designed for a lithium polymer or lithium-ion battery. Do not use a NIMH/NICD/LIFEPO4/LEAD ACID charger. If the charger can support different battery types, make sure to select the Lithium Polymer (Li-Po) mode on the charger.
- User should always charge batteries in an open area away from flammable materials, liquids and surfaces.
- Never charge batteries inside of your drone
- Never charge batteries below freezing (0°C, 32°F)
- Never charge Batteries that are hot to the touch (above 100° F).
- The charger should never be set to charge batteries at a rate greater than 1C (one times the capacity of the battery in amp hours)
- Never overcharge batteries over their rated maximal voltage (4.2V/cell for a LiPo).
- Using a Li-Po sack is suggested when charging to ensure the charging safety. Stop charging when the battery is fully charged.
Discharging Li-Po Batteries
- Never discharge batteries at amperage rates higher than specified on the label
- Never allow the temperature of batteries to exceed 140° F during discharge.
- Never discharge battery to a level below 3V per cell under load. For most drone batteries, the recommended cut off voltage is 3.5V per cell.
- Batteries can still accidentally leak for about an hour after discharge, and that reaction with air may cause the chemicals to ignite. Keep batteries in a safe area away from any combustile materials and observe them for an hour after discharge.
How To Store Li-Po Batteries
- Never store loose batteries together. The batteries’ terminals may contact one another, causing a short circuit.
- Never store batteries in extreme temperatures or direct sunlight. The battery should be stored within -10℃~45℃ range environmental condition. If the battery has to be stored for a long time (more than 3 months), the environmental condition should be:
- Temperature: 23±5℃ Humidity: 65±20%RH
- The voltage should be 3.6V~3.9V range per cell.
- Always disconnect Batteries when not in use and store batteries in a non-conductive and fireproof container.
- Never alter, puncture or impact Batteries or related components.
General Li-Po Safety
- Never strike a battery with any sharp edges
- Never open or deform the folding edge of a cell
- Never drop, hit or bend batteries
- Never disassemble the cells. The disassembling may generate an internal short circuit in the cell, which may cause gassing, firing, or other problems
- Never incinerate nor dispose of batteries in fire. These may cause firing of the cells, which is very dangerous. Additionally, never be soak batteries with liquids such as water, and especially not soft drinks, juices or coffee (never thought I would have to add that one as a tip!).